One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,17)(12,21)(13,15)(14,18)(16,19)(20,22)(23,24)(25,26,31,29)(27,34,37,32)(28,38,33,30)(35,40,39,36)(1,2)(3,4)(5,6)(7,8)(9,11,16,13)(10,17,19,15)(12,20,14,23)(18,24,21,22)(26,29)(30,38)(32,34)(36,40)(2,6)(3,7)(9,12,16,14)(10,18,19,21)(11,20,13,23)(15,22,17,24)(25,27,31,37)(26,32,29,34)(28,39,33,35)(30,36,38,40)(9,13,16,11)(10,15,19,17)(12,20,14,23)(18,24,21,22)(25,28)(26,30)(27,35)(29,38)(31,33)(32,40)(34,36)(37,39)(1,3,5,7)(2,4,6,8)(9,14,16,12)(10,18,19,21)(11,20,13,23)(15,24,17,22)(25,29,31,26)(27,32,37,34)(28,38,33,30)(35,40,39,36)(1,4)(2,7)(3,6)(5,8)(9,15)(10,11)(12,22)(13,19)(14,24)(16,17)(18,20)(21,23)(25,30,31,38)(26,33,29,28)(27,36,37,40)(32,35,34,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.